'''
Created based on the information from:
https://docs.python.org/3/library/http.client.html

Xiannong Meng
2015-09-12
'''
import http.client
import sys

class MyHttpClient():

    def __init__(self, s, p = 80):
        """
        Creates the client object with server url 's'.
        Parameters:
           s: host name in the form of www.abc.com
           p: port number, default is 80
        Pre:  s is a valid www host name
        Post: a connection is established so the client
              can retrieve information from the server.
              If the response code is not 200 (OK), the
              client simply quits.
        """
#        print("host : port : ", s, p)
        self.conn = http.client.HTTPConnection(s, p)

    def request_HEAD(self, page):
        """
        Request header information.
        Pre:  a connection has been established with the server.
        Post: the header information is retrieved.
        """
        self.conn.request("HEAD", page)
        self.res = None
        try:
            self.res = self.conn.getresponse()
            if (self.res.status != 200):
                print("Response code error.");
                sys.exit(1)
            else:
                data = self.res.getheaders()
                print(data)
        except http.client.ResponseNotReady:
            print("sorry, server is not ready.")
        except http.client.BadStatusLine:
            print("sorry, bad status line.")

    def request_page(self, page):
        """
        Request a particular web page
        Pre:  a connection has been established with the server.
        Post: the specified page is retrieved.
        Parameters:
        page: the web page to be retrieved
        """
        self.conn.request("GET", page)
        self.res = None
        try:
            self.res = self.conn.getresponse()
            if (self.res.status != 200):
                print("Response code error.");
                sys.exit(1)
            else:
                data = self.res.read()
                self.data_type = self.parse_header(self.res.msg)
                if self.data_type.cat == "text":
                    print(data)
                elif self.data_type.cat == "image":
                    wf_name = "outf." + self.data_type.type
                    f = open(wf_name, "wb")
                    f.write(data);
                    f.close
                          
        except http.client.ResponseNotReady:
            print("sorry, server is not ready.")
        except http.client.BadStatusLine:
            print("sorry, bad status line.")

    def parse_header(self, msg):
        """
        Parse the information from HTTP header
        (at this moment, only the category and type are extracted)
        Parameters:
          msg: the HTTP header
        Return: an object with two fields, 'cat' and 'type'
        """
        c_type = self.res.getheader("Content-type")
        content = type('typeclass', (object,),
                       {'cat':'', 'type':''})()
        content.cat = "text"     # default!
        content.type = "html"
        if c_type.find("image") != -1:
            content.cat = "image"
        if c_type.find("jpeg") != -1:
            content.type = "jpeg"
        elif c_type.find("png") != -1:
            content.type = "png"

        return content

    def print_info(self):
        """
        Print informatoin about this object
        """
        print("Hi I am here.")

if __name__ == "__main__":

    """
    sys.argv[1]: host in the form of "www.host.com"
    sys.argv[2]: port, default 80
    sys.argv[3]: web page, in the form of "/index.html"
    """
    if len(sys.argv) != 4:
        print("usage: python httpclient.py host port path")
        sys.exit(1)

    client = MyHttpClient(sys.argv[1], sys.argv[2])
#    client.print_info()

    client.request_HEAD(sys.argv[3])
#    client.request_page(sys.argv[3])